Auditory and Vestibular Flashcards
What are the cilia on hair cells responsible for?
Stimulus-responsive cation entry, cell body releases glutamate onto efferent nerve endings, afferent nerves regulate the response
What is sound?
Repetitive variations in a medium, such as air
Vibration of the eardurm, the malleus, the incus and the stapes spreads to the _____ where it is converted into movement/vibration of ______. The vibration in the cochlea is captured by ____ _____. Then via ___________ physical vibration is converted to neural energy which is percieved in the auditory cortex.
Vibration of the eardurm, the malleus, the incus and the stapes spreads to the cochlea where it is converted into movement/vibration of fluids. The vibration in the cochlea is captured by hair cells. Then via transduction physical vibration is converted to neural energy which is percieved in the auditory cortex.
What are the three mechanisms for impedance matching?
1) Area ratio of the ear drum to the stapes footplate (20:1)
2) lever action of the ossicles
3) bucling of the ear drum
The cochlea consists of three ______ _____ cavities
The cochlea consists of three fluid filled cavities
what separates scala vestibuli from scala media?
reissner’s membrane
what separates scala media from scala tympani?
basilar membrane
what is the path of conduction through the cochlea?
organ of corti hair cells -> basilar membrane to tectorial membrane
Where is scala media closed off?
At the apex
What connects ar the helicotrema?
Scala tympani and scala vestibuli
perilymph in scala _______ and scala _______ is continuous
perilymph in scala tympani and scala vestibuli is continuous
Scala tympani meets ____ window
Scala vestibuli meets _____ window
Scala tympani meets oval window
Scala vestibuli meets round window
pressure at oval window results in what?
Complimentary motion at round window
The middle of the basilar membrane vibrates for ____ frequency sound as it is _____ stiff and more ____.
The middle of the basilar membrane vibrates for lower frequency sound as it is less stiff and more wide.
The _____ and __________ of the basilar membrane determines the distance a particular frequency travels
The width and flexibility of the basilar membrane determines the distance a particular frequency travels
Where are hair cells located?
Between basilar membrane and reticular lamina, tips in the tectorial membrane
what are the two types of hair cell and what separates them?
inner (3500)
outer (15,000- 20,000)
separated by rods of corti
where do hair cells synapse?
on bipolar neurons with cell body in spiral ganglion
Describe hair cell transduction
The tectorial membrane vibrates and the hair cells (cilia) bend.
Depending on how they bend the hair cells release neurotransmitter.
The neurotransmitter released in the hair cell are captured in nerve fibres.
The hair cell K current is _______
The hair cell K current is inwards
Endolymph potential is __mV so generating a ___mV gradient across the stereocilia membrane
Endolymph potential is 80mV so generating a 120mV gradient across the stereocilia membrane
_____ hair cells are the main source of afferent signal in auditory nerve (__ afferents per hair cell). multiple outer hair cells are innervated by a ______ afferent.
Inner hair cells are the main source of afferent signal in auditory nerve (10 afferents per hair cell). multiple outer hair cells are innervated by a single afferent.
Outer hair cells primarily get _______ inputs, controls _________ and ______ membrane vibration.
Outer hair cells primarily get efferent inputs, controls stiffness and amplify membrane vibration.
Outer hair cells are often called the …..
Cochlear amplifier
Which protein can change the length of the cell?
Motor protein composed of prestin- changes the relationship between basilar membrane and tectorial membrane
Outer hair cells respond to sound with both a ________ _________ and a change in ______
Outer hair cells respond to sound with both a receptor potential and a change in length
How does furosemide affect outer hair cells?
Inactivates the membrane motor